Meade LX200 GPS computer connect

[Atmos]

Over the last few years i have been trying to connect my LX200 to my computer, but to no avail.
I now have four different USB to RS232 serial adapters. I have tried to connect through three different computers.
1) An older 17" MacBook Pro running Windows XP SP3 through Bootcamp.
2) A three year old dirt cheap Compaq running Windows 8.1.
3) Now a new 15" MacBook Pro running Windows 8.1 through Parallels.

For years I have just assumed that it didn't like XP running through Bootcamp or just didn't like Windows 8.1. Now I am starting to question whether either of the RS232 ports on the telescope actually work!

I have tried running it through the Meade Autostar Suite to begin with, attempted Maxim DL and more recently (last week) TheSkyX. Currently using an FDI (or close to that) USB to Serial cable, the other half (RS232 to DB9) is what I bought from Bintel, Meade products. Downloaded the latest drivers last week so that's all up to date.

When trying to connect to the telescope it does recognise that it's there and but eventually times out after several communication attempts. I am stuck!!

So, has anyone had similar troubles with a LX200 GPS or may have some idea on how to fix the issue?

Cheers,
Colin

[AndrewJ]

Gday Colin

What firmware version do you have loaded?????
The comment
would indicate the scope is working.
Have you tried on a real PC with a real com port ( as that will confirm absolutely if its the scope or not )
There is a factory test routine that can be run, but you need a special loopback cable to run it.
There is a also a bug in the ASCOM drivers that can result in timeouts if there is no response within 5 seconds.
To test for that, you can try to connect using my PEC editor ( grab the beta at the bottom of the page )
http://members.optusnet.com.au/johansea/
It uses native comms to try and detect a Meade scope, and doesnt fail on small timeouts.
You could always run that and see if it finds the scope
( save the log file for reviewing if it does )

Andrew

[Atmos]

Thanks for the link Andrew, I have given it a shot this morning but it was a failure. It found the only active COM port at the time (COM4), ran through all the BAUD rates but wasn't have to find the telescope. I have uploaded the log file with it.

It is currently running 4.2G but I am unsure as to whether there is an update from there anyway. I know this version was released near a decade ago though.

I have considered trying to track down a older computer with RS232 connections but I have been hesitant to go through all that just to see whether the port on the telescope works.

[AndrewJ]

Gday Colin
4.2G is the latest firmware for the LX200s.
I note in the log that some dross got returned at times
so not sure if that is real or not, or an artifact from the scope or converter.
Another test you could try is to start the scope in safeload mode
( use 999 on booting ). Once it boots,try and connect using my app..
Then just turn off the scope.
The safeload region has its own copy of the rs232 comms code
so if it works and the normal doesnt, it may just be corrupted data.
Note! You must use the rs232 port alongside the Hbx socket for this test, as the safeload code only recognises that channel.
Andrew

[Atmos]

Andrew,

Used that RS232 port, pushed "999" and it came up with the "Downloading" message on the Autostar II which I assume is what it was supposed to do. I have linked the log from that session as well. I note that it is a little different, not sure why though, I don't really understand what its outputting to be honest.

Thanks a bunch for your input :thumbsup:

[AndrewJ]

Gday Colin


It again looks like noise on the line.
As i mentioned earlier, there are 2 different versions of rs232 comms code in the firmware. One is in the normal region and one is in the safeload region.
Meade use a std command called "Ack", where you send a Hex 06 to the scope and it replies with a single byte.
You should get back 'D' if you are in download mode and
either 'A' or 'P' ( for AltAz or Polar ) in normal mode.
If it gets no reply, i also try using the :ED# and :EC# commands
as these can detect a parked scope ( which doesnt respond to Ack )

In the following lines from the log
the Write [06] is where my app sends the #x06 Ack at 9600baud

0000.057 user Test Current Baud : 9600
0000.058 Write [06]
0000.072 Read [BF]

but what comes back is [BF] ie hexadecimal xBF
No idea where this comes from, and it may just be junk
in the buffer, or a real ( but corrupted ) response.

Andrew

[AndrewJ]

One other thing
Have you actually confirmed that the cable itself is wired correctly???
I have seen junk data like yours at times when i used a long "but disconnected" cable.
A simple loopback test with something like hyperterminal can test for that.

Andrew

[Atmos]

Considering that there is some "responses" at bauds other than 9600, sounds like noise. The cable isn't exactly short either so that could be it, as you say.

When I first started trying to connect years ago I bought the cables from Jaycar, after they didn't work I caved in and bought all of the stuff from Bintel (the Meade labeled products) so I assumed that it would all be wired up correctly!

I can have a look at the cable but electronics isn't really my forte :(

[AndrewJ]

Gday Colin
Just for info, in the US, there was a spate of wrongly wired Meade cable adapters a while back :( Its not impossible some got out here.
( They were wrongly connected inside the black DB9 to RJ12 adapter. )
Do you have a simple multimeter to do a continuity test??

Andrew

[Atmos]

I have probably got one laying around, if I don't I have a friend that does.

I am guessing that it needs to be configured the same way as:
http://obs.nineplanets.org/meade/cable.html (DB9 is about half way down the page on the right).

The Multimeter that I may have around somewhere I believe was for heavier currents than this so I don't think that it'll fit into those plugs.

[AndrewJ]

Gday Colin
That diag is no good as its for the "Classic" LX200 ( and confusing ).
Lots of info on Weasners ETX site re cables and testing,
but i always use this one i made up.
If the multimeter probes are too thick, just sticky tape a needle or sewing pin to each one. Works well enough for simple continuity testing ;)

Andrew

[Atmos]

I think what I am currently going from one end of the RS232 (plugged into telescope) and the other end us Ground in correct spot but Misc Serial and RX are both active.

When I plug it into the RJ11-DB9 I can get the Ground in the correct spot but only getting one other connection.

[AndrewJ]

Gday Colin
Im not sure i understand your comments.
Inside the scope the "Misc" serial in/out pins are connected to the real Tx/Rx
ie there are 2 paralleled Tx and 2 paralleled Rx pins in the scopes single socket.
You need to check your ( fully unplugged ) Meade cable, between the holes in DB9 connector, and the pins in the RJ12 connector

Andrew

[Atmos]

Andrew,

Didn't explain myself very well at all.
I've had the cable plugged into the telescope and I was testing the other end of it. Had one terminal on the Ground, the next two were active (Misc Serial Out & RX) and then nothing from the following two (TX & Misc Serial In). I am guessing that it means the cable may be miswired or something?

I have been testing the DB9 adapter when it's been plugged into the cable and plugged into the telescope. I'll have to put some batteries into the multimeter then I guess to test it unplugged.

[thunderchildobs]

Have you tried connecting your computer / software /cables to a friends scope? The scope type shouldn't matter as you are just testing your setup. If you cannot connect, you know your stuff is the problem and not your scope. Or conversely can a friend connect to your scope?

[AndrewJ]

Gday Colin
I have no idea what to expect when plugged in the way you describe.
The PC Rx line may show something, as that is data being sent from the scope ( and the scope is the master controller ). The PC Tx line would not normally show anything ( as its not connected to the PC ) as the PC is the master in that case.
You really need to do a continuity test of the cable when it is unplugged to confirm its wiring is correct.

Andrew

[Atmos]

I don't have any problems running my EQ6 via EQMOD so the computer itself doesn't have any issues talking to a telescope, just this one.



Oh I was under the impression that all of the testing needed to be done while it was connected to the telescope. I'll have to test it out tomorrow evening on my friends multimeter, the one I've been using is about 30 years old and is no longer able to be self powered without some internal repairs.

[AndrewJ]

Gday Colin
Nope, not yet.
Its a process of elimination so we test each bit in the chain by itself.
You mentioned EQMod worked, so the PC and USB2Ser adapter shld be OK, but EQMod ( in PC Direct Mode ), uses a differently wired cable from the USBConverter to Hbx/Scope than the Meades do, so we need to confirm your Meade specific cable is wired correctly. ( Some of these were known to be miswired, hence why we need to test it by itself )

Andrew

[Atmos]

Hello Andrew,

Had a play around with my cables and connecters last night, found that everything seems to be wired up correctly. So, not a cable issue :/ If it was that it would be such an easy fix!

So, after a dozen or so "towel throw-ins" I think I am just going to resign to the fact that my LX200 is a bit of a electronic dud.

Don't get me wrong, works perfect in every other aspect, just dud RS232 ports.

[AndrewJ]

Gday Colin
The final test would be to find someone nearby who has a setup that works and see if their setup can detect your scope.
Other than that, it may be a dead rs232 chip on the mainboard.
I know in the states, some people have replaced these in an attempt to get it working ( and some succeeded ), but its a finnicky job and needs a skilled operator with the right tools.

Andrew

[Atmos]

Andrew,

Thanks again for all your help and advise. I'll see if I can track down someone in to Greater Melbourne area that has a LX200 setup, I don't personally know anyone with one.

I'll did a quick Google search and it sounds like the chip itself is pretty easy to get your hands on. I have a good mate that is an electronic engineer so I think I'll be paying him a visit ;)

[AndrewJ]

Gday Colin


What suburb are you in?
There are probably lots of LX200s in Melb.
I am near BINTEL if that is close enough.



There are full schematics of the LX200 on the yahoo site, and the chip is a std max232 ( ie dime a dozen ). It is surface mounted, but is in an easy to get to spot, so he could probably also test it in situ for proper voltage levels etc.

Andrew

[Atmos]

Andrew,

I live just up in Greensborough so not that far from there. I imagine that there would be a considerable number of LX200 owners around the place.

I'll probably be seeing my mate next week so I might take my scope around then and do a powe test as you suggest. Hopefully source a Max232 chip before then.

[Don Pensack]

Did you install the serial port simulation program on the computer? Without that, it won't recognize the connection.
Did you get the proprietary Meade cable? Meade wires the ports in a different sequence from normal com ports so the RS232 cable has to be wired differently.